1. Technical Field
The present invention relates to a method for manufacturing gas generating material, and in particular relates to a method for manufacturing a gas generating material which contains an azide and a metal oxide and is used for generating gas to inflate a vehicle occupant restraint, such as an airbag.
2. Description of the Prior Art
U.S. Pat. No. 3,996,079 discloses a process for manufacturing an azide-containing gas generating composition. The dry ingredients of the gas generating composition are mixed together. A liquid is then added to the dry mixture to produce a plastic mass. The plastic mass is then forced through a die, perforated plate, or sieve to form wet granules. The wet granules are then dried.
U.S. Pat. No. 4,758,287 also discloses a process for manufacturing an azide containing gas generating material. In this process, a water slurry of gas generating material is prepared. The slurry is then molded into a desired shape and flash dried.
The particle size of the ingredients in a gas generating material is an important factor relating to performance of the gas generating material. Generally, the smaller the particle size of the ingredient the more active the ingredient when the gas generating material is ignited. Therefore, grinding an ingredient of a gas generating material to reduce its particle size is common practice.